NON-CRT Displays that support 15KHz and 25KHz resolutions

[twistedsymphony]

I got my NEC MultiSync LCD1970NX in... and while I haven't got the connectors in to use the Test Pattern Generator I realized that... hmm I've got a NAOMI sitting on my bench that can support 15KHz mode and outputs over VGA... lets hook that up...

here you go:

the menu info screen not only calls out the horizontal refresh but also the model number...

so far I really like this monitor, it's really well constructed.. VERY heavy for an LCD but the stand is rock solid and acts like an (extremely smooth) turn table so you can swivel the monitor, also has height and tilt adjustment.

480P VGA image quality isn't quite as sharp as my Hyundai L90D+ (my old bench monitor that this will be replacing) and 480i looks like hot garbage as you can see in the image above (then again 480i looks like hot garbage on everything)... I'm anxious to see how 240P resolutions look.

FWIW I know for a fact the old L90D does NOT support 15K mode because it's been fed that on a number of occasions while setting up CRT_EmuDriver for my GroovyMAME PCs... speaking of which this LCD will be an enormous benefit for that task since it will be able to accept everything from 15K up through the normal default PC resolutions.

 

[defor]

I must have missed the part in the first post saying the 2070NX doesn't do below 31k....

it definitely DOES NOT as I just got one in today... at least it was moderately cheap.

guess I'll have to go with 1970's and make some space fillers for my IKEA cocktail since it's cut for dual 20"

 

[Darksoft]

I have spotted a BenQ G2412HD, that could fit very well in my cabinet. Has anyone tried it? The specs says that it supports Horizontal: 24 ~ 83 (KHz), Vertical: 50 ~ 76 (Hz).

 

[defor]

I got my NEC MultiSync LCD1970NX in... and while I haven't got the connectors in to use the Test Pattern Generator I realized that... hmm I've got a NAOMI sitting on my bench that can support 15KHz mode and outputs over VGA... lets hook that up...

So I did the same thing.....
Just got a nice LCD1970NX in the mail today...
But I've got MAJOR issues:


So based on that it should be fine right? Same refresh rates, etc that you were seeing.
Notice that wierd banding across the border between Green and Blue? - check the Naomi logo:


So, on a Naomi this is what happens- it ALMOST looks perfect, but the strange interlace errors in the middle are a deal-breaker.
When the vertical position is adjusted, the interlace location stays the same relative to the screen, and the video source moves up and down as expected.

but on a System 256.... it gets real CRAZY:

Here's the a video I took:
https://www.youtube.com/watch?v=wb26M01JHqo

SO, I've got the exact same model monitor, simply a newer serial number- 31k and better looks fine.. at least 15k SHOWS... but it's not really usable for the long run as you can see...

Got any suggestions?
I've also taken some photos of the control board and the serial number stickers- It'd be interesting to sit how they compare.

If you want, I can also dump the 256K flash chip as well- it's data sheet is:
http://www.amictechnology.com/datasheets/A290021.pdf

 

[defor]

I checked my firmware ID/Version:

F/W ID CB9SSP10
F/W VER. 1.2.05

you can see this by going to the service menu:
enter the frequency display
press select and reset together
when you get the prompt, press select again

Service manual here- nothing seems changeable that affects this but i'm curious what firmware version you may have...
http://archive.espec.ws/files/NEC 1970NX.pdf

 

[twistedsymphony]

I can't see the video you posted as it's apparently blocked on copyright grounds.


as for my monitor's firmware revision:
F/W ID C59SLP10
F/W Version 1.1.10

Also according to this screen the total "on" time for my monitor is 34853 hours O.o

I still haven't tested any 15K sources other than NAOMI in 480i mode. though the interlace pattern isn't terrible. I also used the "auto adjust" feature to size the image to the screen.

 

[defor]

DAMMIT YOUTUBE.

here's the file in my dropbox:
https://www.dropbox.com/s/1s27u972ixtr9ew/IMG_1027.m4v?dl=0

 

[twistedsymphony]

DAMMIT YOUTUBE.

here's the file in my dropbox:
https://www.dropbox.com/s/1s27u972ixtr9ew/IMG_1027.m4v?dl=0

that's interesting... maybe you need a sync inverter.

different games output positive or negative sync, it's possible that the monitor only supports one type (probably negative I think that's the most common) and the 256 outputs the other.

building a circuit to correct for this would be as simple as hooking it up to a not gate, or wiring a transistor to act as an inverter.

 

[defor]

Possible, but( to a lesser extent) the same issue exists on the Naomi, and as you can see the sync polarities are the same as yours.

In the meantime, I've looked at the control boards on the 1970nx, and there appear to be two different part numbers- I'm looking to get my hands on the older model,one, in hopes that the older firmware/ pcb fixes this, two, to see if I can run that firmware in the 2007 model I have

 

[twistedsymphony]

Maybe I'm picking up something different than what you are but what I see in your NAOMI screenshots are interlacing artifacts, which are directly effected by the de-interlacing algorithms used by the monitor. what I see in your 256 video is that the monitor is failing to register the blanking signal at the end of each line at a very regular and consistent interval, which says to me there is a sync signal issue.

What resolution is the 256 outputting?

 

[defor]

well- the naomi does NOT show a clean boot logo as you can see in the photo - that's a static screen. - compare to your photo- there's a messed up interlace pattern right across the middle of the display on static images

the 256 DEFINITELY is being detected as the wrong resolution:
680x226
H 15.7KHz
V 59.7Hz
H NEG
V NEG

-- I don't consider what's happening on the naomi to be interlacing artifacts..

On a grid screen or service menu, the effect is even more pronounced, and the lines in that part look ... shuffled (yours left, mine right)
I can get a better photo tonight if you still aren't seeing it...?

 

[twistedsymphony]

indeed your NAOMI images doesn't look correct. I just think it's a completely different problem than what you're seeing on the 256.

the reported resolution of 680x226 lends a bit of credence to the blanking signal not getting caught since it's nearly double the horizontal resolution that it should be.

are you running just a straight VGA cable?

 

[defor]

yep straight VGA- no matter what I do, I cannot get rid of that issue on the naomi.
I've ordered one of the older control PCB's off eBay today, in hopes that I can either swap, or see about refreshing the other, if it's simply a difference in flash.

the reported resolution of 680x226 lends a bit of credence to the blanking signal not getting caught since it's nearly double the horizontal resolution that it should be.

While true, I'd worry less if the Naomi showed correctly on here, while it shows just fine on my CRT's.
if you see the interlacing effects in person, it looks very related, all the same.

 

[twistedsymphony]

damn, I hope the older board revision sorts this out.

 

[twistedsymphony]

got the 256 up and running today, it does display on my monitor in 15K mode. it's actually a weird resolution of 680x452i (31K mode is normal 640x480P)

so yeah, it definitely seems as though it's a monitor thing and not a 256 thing.

on another note I'm pretty surprised/disappointed that the 2x6 hardware runs interlaced mode for 15K, though I tested it with both the Capcom I/O and Sega Type 3 and it happily works with both... or at least it does with this game.

 

[defor]

thanks for verifying it being a monitor issue on my side- IF it ends up being fixable via flash swap (I'll be socketing the flash chips anyway), I'll dump the old firmware and post it up here if anyone else runs into this annoying thing.

 

[Derick2k]

T, which lcd monitor would you recommend? I want to get something to use for sort of a testbench setup.

 

[defor]

Woo! It works!

Swapped the main logic pcb, and 15k looks nice, no more wierd interlace tearing- some flickering in the interlace as you mention but good enough for casual play/test bench usage.

Doesn't fill the LCD vertically completely, but this is technically CORRECT.. the screen at native resolution is NOT a 4:3 lcd.

Interestingly, on the System 256, when the "Loading" screen is shown on Zeta Gundam, it's showing the proper 240 vertical resolution...
Strange that the game changes it, BUT technically the PS2 has multiple GS modes that software CAN utilize, and the game may simply use a nonstandard one.

Now to fit an LM1881, so I don't have to worry about separate sync.

thanks for the help twistedsymphony!

Once I find my spare PLCC32 sockets I'll see if "updated" boards can be refreshed back to the old firmware (1.1.10) with the same results.
I'm really liking this monitor, cheap, easy to find, and nice styling.
If only the 20" variant worked below 31k...

 

[defor]

If only the 20" variant worked below 31k...

On the off chance that perhaps I could drive the 20" LCD2070NX with the LCD1970NX board, I disassembled the monitor- the entire PCB is MAJORLY different, so it's not surprising in the least that it won't do 15k.
the main chip is an MSTAR MST9251-LF instead of the Genesis gm5221-LF

 

[twistedsymphony]

T, which lcd monitor would you recommend? I want to get something to use for sort of a testbench setup.

I bought an NEC 1970NX and so far it has been able to sync to the 15K signals from a NAOMI and a System 256, I've heard that the 1970VX works as well HOWEVER... defor bought the same model and was having sync issues on 15K from NAOMI and System 256. He's speculated that it's due to having a newer revision control board/firmware. There seems to be two control board revisions and they do sell on eBay since this was a monitor designed for industrial application. So it seems you'd want to seek out the 1970 models with the older control board revision.

Interestingly, on the System 256, when the "Loading" screen is shown on Zeta Gundam, it's showing the proper 240 vertical resolution...
Strange that the game changes it, BUT technically the PS2 has multiple GS modes that software CAN utilize, and the game may simply use a nonstandard one.

So glad to see you got this up and running.

the video mode switching doesn't surprise me as my DDR System 573 does the same thing, all menus and text screens run in 480i and game play runs in 240P. the switch is absolutely seamless since the sync signal doesn't even have so much as a hiccup and it just goes from one frame at 480i to the next frame at 240P without missing a beat.